Method of preparing waterresistant containers



Dec. 25, 1945. 1. MCHENRY METHOD OF PREPARING WATER-RESISTANT CONTAINERS Fiied March 2o, 1942 2 Sheets-Sheet l I l n Illllllllllllllllll l. MCHENRY METHOD OF PREPARING WATER-RESISTANT CONTAINERS Filed March 20, 1942 2 Sheets-*Sheet 2 y? e w Perenfed pee. 25, 1945 METHOD F PREPABING WATER- RESISTANT CONTAINERS Irving McHenry, River Forest, Ill., assigner to Mld-States Gummed Paper Co., Chicago, Ill., a corporation of Delaware Appueauon March zo, 1942seria1No. 435,478

s claims.

tainer such as a cardboard boxior carton which y is substantially resistant to moisture. Another object is to provide for the closing 'of the open joints of a, box or carton in such a manner as to permit the application oi a thin coating of .a water-resistant material to the entire outer surface of the box or carton. Still another object isto apply a sheet of material over the open joints of the container with the sheet material disposed in overlapping relation with respect to the walls of the container adjacent the joints. Yet another object is to provide a' junction between'the overlapping sheet material and the walls of the container which is extremely thin and is adapted to receive `a thin coating of a water-resistant material which will extend over the junction.

Another object is to seal a container such as a box or carton with gummed tape, the gummed tape being disposed over the open joints of the box or carton and extending over the walls of the container adjacent the open joints in overlapping relation with the walls. Another object is to provide strips of gummed tape sealing the open joints of the container, with the entire periphery of each of the strips being in sealing relation with the walls of the container.

A further object is to provide va. doublecontainer structure in which one container is disg drawings in which:

Fig. 1 is a perspective view of a cardboard box showing the strips of gummed tape applied thereto; Fig. 2 is a fragmentary transverse sectional view taken along the line 2-2 of Fig. 1; Fig. 3 is a fragmentary detail sectional view of a portion of the container wall shown in Fig. 2 with the water-resistant particles applied to the outer surface thereof; Fig. 4 is a fragmentary detail sectional view corresponding to Fig. 3 and showing the water-resistant coating on the outer surface of the wall of the box; Fig. 5 is a fragmentary sectional view corresponding to the view of Fig. 2 and showing la modification of the invention; Fig. 6 is a fragmentary perspective view showing the application of a strip oi.v gummed tape in accordance with a 4rnodiiication of the invention; Fig. 7 is a fragmentary perspective view of the same modication showing one step in the application of the strip of gummed tape; Fig. 8 is a fragmentary perspective view of the same modification showing a second step in the application of the gummed tape; Fig. 9 is a fragmentary perspective View of' the modication shown in Figs. 6, 7 and 8 illustrating the box after the application of the tape; Fig. 10 is a fragmentary detail sectional view of a wall of the 4box showing a strip of tape applied thereto with the edge of the tape being tapered; Fig. 11 is a perspective view partially broken away show--l ing a modification of the invention wherein ,one box is disposed within another; Fig. 12 is a longitudinal sectional view partly broken away taken along. the line i2--l2 of Fig. 11; Fig. 13 is a longitudinal sectional view similar to that of Fig. 12 showing the inner box in shifted position; Fig. 14 is a transverse sectional view taken along the line |4-l4 of Fig. 12; and Fig. l5 is a transverse sectional view corresponding to the view of Fig. '14 showing the double container when the side walls are subjected to pressure.

The invention contemplates the forming of a container from cardboard, paperboard or the like which will be substantially resistant, not only to atmospheric humidity, but also to the direct application of water to the container; In providing such a container the entire outer surface of the container may be treated with a substan- .tially Vwater-resistant material to waterproof the container.

In the treatment 'of a container of cardboard or the like with a water-resistant material, the l forming of a continuous coating over the entire outer surface of the container presents certain problems, particularly with respect to the closing of the joints of the container. In accordance with the present invention the closure of such joints is carried out by the application oi a sheet material such as gummed tape which extends over the open joint and is sealed to the Walls of the container adjacent the edges of the same in overlapping relation .with the wall. The junction which is formed between the gummed tape and the wall of the container is preferably as thin as possible in order to permit the appliare joined by a strip of reinforcing tape Il which is of relatively heavy material and provides the necessary strength for securing these walls to each other. In the usual construction of cardboard boxes or cartons a single joint of this character serves to provide for the assembly of the box.

As seen particularly in Fig. 2, the end wall I1 of the box may consist of an inner wall I3, an outer wall 20, and a corrugated section 2| therebetween. In the usual box construction as illustrated, all of the walls of the box may be of this same construction.

In assembling the box the strip I3 of heavy reinfoming tape, which may be of sisal tape Vor other suitable material, is applied across the open jointformed by the walls I6 and I1 and is secured to the walls adjacent the edges of the joint. Over the strip I3 of sisal tape is placed the strip of gummed tape I4, the strip I4 being larger than the strip I8 so that the edges of the gummed tape extend beyond the edges of the sisal tape and the gummed tape about its periphery is secured directly to the walls of the box rather than to the sisal tape. As seen particularly in Fig. 2, this construction provides junctions 22 and 23 at the edge of the gummed tape which are extremely thin and which are adapted to receive a thin continuous coating. of a water-resistant material such as wax or the like.

When the sisal tape I8 and gummed tape I4 have been placed in position on the corners oi the box the water-resistant material, which may consist of paraffin wax or the like, may be applied to the outer surface of the box in the form of extremely small particles 25. Preferably these particles are formed on the outer surface of the box by spraying the wax particles thereon. The wax may be in liquid form as it passes through the spray and the particles which are sprayed will solidify by the time that they engage the surface of the box and will thus form small soli particles on the surface of the box. When the particles are brought into engagement with the surface of the box they should be suillciently tacky to adhere to this surface. As seen in Fig. 3

`the particles adhering to the surface of the box normally will be dat on the side which engages the surface of the box, but in other respects will be globular in character.

The box carrying the particles of wax (Fig. 3) may be subjected to heat to melt the particles and cause them to ilow together forming a substantially continuouscoating 24 extending over the outer surface of the box and over the surface of the strips of gummed tape applied thereto (Fig. 4). By reason of the use of the thin strips of gummed tape on the surface of the box the junction formed by the overlapping of the gummed tape on the walls of the box will be so thin that the layer 24 will extend in continuous form over this junction, as seen at 23.

Preferably the wax lwhich is sprayed on the surface of the box contains a small quantity of a material which tends to prevent crystallization of the wax or other water-resistant material, for

example, approximately by weight of diathylene glycol abietate rin.

The wax is preferably prayed with an air spray in .which -the air used possesses a relative humidity of between 50 and 100%. Air having a relative humidity of 50% has been found to be particularly suitable for this purpose.

Asseen particularly in Fig. 5, the walls It and I1 may be joined by applying the heavy strip I3 of reinforcing tape to the inner surface of the box. In this manner the strip Il'A is applied to the inner surface of the walls Il and I1 and is adhesively secured to these walls to join the walls together. A strip of gummed tape |4l may then be applied to the outer surface of the walls I6 and Il and will extend across the open joint formed by these walls. The strip o f tape I 4* is adhesively secured to the walls il and Il adjacent the open joint and is adapted to receive the coating 24 of wax or other water-resistant material.

In the embodiment of the invention shown Figs. 6, '7, 8 and 9, a strip of gummed tape 21 is applied to the closure flaps 28 and 29 of a box 3l. The closure flaps are placed in adjacent relation so that the edges are adjoining and form an open joint across which the tape 2l is placed.

The open joint formed along the line 2| between the closure flaps 28 and 23 and the side wall 32 of the container is sealed by the use of a strip 33 of gummed tape. The strip 33 of gummed tape is applied to the sidewall 32 of the box with one longitudinal portion of the tape being adhesively secured to the side wall 32 and another longitudinal portion extending upwardly above the top of the box. The strip of gummed tape 33 is longer than the side wall 32 l of the box and so provides end portions and 2l which may be folded rearwardly upon the end the box is then cut transversely along a pair of lines 'which are in alignment with the corners 31 and 38 of the box to form the slits 33 and 40. The longitudinal portion 4| extending upwardly above the top of the box is then folded over the open joint 3| and adhesively secured to the upper surface of the closure flaps 23 and 23, as seen in Fig. 8. The end portions 42 and 43 adjacent the upper longitudinal portion 4| are then folded downwardly and adhesively secured to the upper surface of the portion 4| and the closure flaps 23 and 29 (Fig. 9).

With the arrangement of the strip of gummed tape as shown in Figs. 6, '7, 8 and 9, all of the peripheral edges of the tape are adhesively secured to the surface of the box or to another surface of the gummed tape. The junction formed by the overlapping edges of the tape is in each case extremely thin and is adapted to receive a continuous coating of a water-resistant material which may extend over the junction.

Referring particularly to Fig. l0, the wall 44 of the box, consisting of the corrugated section 45 and the inner and outer walls 43 and 41 may receive a strip 48 of gummed tape. In order to minimize the diillculty of covering the overlapping junction of the gummed tape with the wall 44 the edge of the strip of gummed tape may be subjected to a sanding operation which produces a taper 49 at the edge of the tape and simplifies the forming of a continuous water-resistant coating over the wall of the box, the tape, and the junction between the two. If desired, the edge of the strip ofgumm'ed tape may be subjected to a bulng operation with sand paper or the like, and for the purpose of simplicity, any

frictional treatment of the edge of the strip of gummed tape will be referred to herein as a buing operation.

In the modification of the invention shown in Figs. 11 to 15 the container includes a pair of boxes 50 and 5| with the box 5| disposed within the box '50. Preferably, as shown, the internal cross-sectional dimensions of the box 50 are substantially the same as the external cross-sectional dimensions of the box thus producing (Fig. 14) a tight fit between 'thesurfaces of the two boxes. At the same time the box 50 is preferably longer than the box 5| so that the end walls 52 and 53 of the box 5| are spaced from, the end walls 54 and 55 respectively of the box 50. This construction provides for movement of the box 5| within the box 50 in a longitudinal direction and when one of the ends of the outer box 50 is subjected to pressure the inner box 5| may move freely to the position shown in Fig. 13 wherein the end wall 53 is brought into adjacent relation with the end wall 55. If the other end of the box 50 were subjected 'to pressure the box 5| could shift in the opposite direction so that the end wall 52 would be in adjacent relation to the end wall 54. v

If the outer box is subjected to pressure on its sides or at any of the corners of the same, the box 5|, although it cannot move laterally within the box 50, will nevertheless be permitted to expand longitudinally under this lateral pressure and any danger of breaking the box 5| is sub` stantiaily avoided.

Both the box 50 and the box 5| may be treated with a water-resistant material which forms a coating about the entire outer surface of each of the boxes. The outer box 50 will then prevent access of water to the material within the inner box unless the box 50 or the coating thereon is broken or destroyed. In this event the box 5| ing of the outer box or the box itself is torn, bent or broken, the inner box will still serve to to protect the inner-box and the coating thereon I from damage.

Although the invention has been described in connection with particular constructions and embodiments of the same, it will be understood that many changes and modifications may be made without departing from the spirit and scope of the invention'.

I claim:

l. A method of treating a container to render the same water-resistant, said container having an open joint formed by the walls thereof, with the edges of the walls disposed in adjacent relation, comprising adhesively securing a sheet of gummed tape over said joint, with the sheet extending across said joint and being adhesively secured to the surface of the walls adjacent said edges; the entire periphery of said sheet being secured to the walls in overlapping relation, applying to the outer surface of the container and the sheet of gummed tape thereon a plurality 'with the edges of the walls disposed in adjacent relation, comprising applying a sheet of reinforcing tape to said jointsaid sheet extending across said adjacent edges of the walls and being secured to the walls, adhesively securing a thin sheet of material over said reinforcing tape, said thin sheet being larger than the sheet of reinforcing tape and extending beyond all of the edges oi' the reinforcing tape, the thin sheet being secured to the walls of the container in overlapping relation therewith, applying to the outer surfacel `oi! the container and the thin sheet a plurality of small particles of a water-resistant material said particles being slightly tacky described in Figs. 1 to 10, inclusive. Similarly,

in applying the water-resistant material to each of the boxes, the method heretofore described 1 may be used.

In assembling the unit the box 5| is iilled with the desired material and then closed. All of the open joints of the box are sealed with gummed tape in accordance with the steps described in connection with the embodiment of the invention shown in Figs. l to 10. The outer surface of the box 5| is then coated with a thin layer of a water-resistant material.

When the box 5| has been treated to provide water-resistance it may then be placed within vmoisture but is also resistant to blows and is very diiiicult to injure or destroy. If the coatwhereby they adhere to said surface, and heating the particles to melt the same and cause them 'to flow together forming a substantially continuous water-resistant coating over the said surface including the junction of said thin sheet with the Walls of the container.

3. A method of treating a container to render the same water-resistant, said container havingan open joint formed by the walls thereof, with the edges of the walls disposed in adjacent relation, comprising securing a sheet ofreinforcing material across saidv joint on the inner side of said container, adhesively securing a thin sheet of material over said joint on the outer surface of the container, with the sheet extending across said joint and being adhesively secured to the surface of the walls adjacent said edges, the entire periphery of said sheet being secured to the walls in overlapping relation, applying to the other surface of the container and the thin sheet of material thereon a plurality loi" small particles of a Water-resistant material, said particles being slightly tacky whereby vthey adhere to said surface, and heating the particles to melt the same and cause them to ow to gether to form a substantially continuous waterresistant coating.

4. A method as set forth in claim 1 wherein the edges of the gummed tape are buried to reduce the thickness of the same along the junction of the sheet of tape with the walls of the container before the water-resistant material is applied to the container.

5. In a method of treating a container to render the same substantially water-resistant, said container having an open Joint formed by the walls thereof, with the edges of the walls disposed in adjacent relation, the steps of adhesively securing a sheet of reinforcing tape to said joint, said sheet extending across said adjacent edges of the walls and being secured to of the same with the walls of the container, and

applying a thin, substantially continuous coating of a water-resistant material to the outer surface of the container and the thin sheet of material including the Junction of the latter with said walls.

6. In a method of treating a container to reni der the same substantially water-resistant, said container having an open Joint formed by the walls thereof, with the edges of the walls'disposed in adjacent relation, the steps of adhesively securing a sheet of heavy reinforcing tape to said joint, said sheet extending across said adjacent edges vof the walls and being secured to the walls, adhesively securing a thin sheet of gummed tape over said sheet of reinforcing tape, said thin sheet being larger than the sheet of reinforcing tape and extending beyond each of the edges of the reinforcing tape. the edges of the thin sheet being secured to the walls of the container in overlapping relation therewith, and bufiing the edges of the thin sheet of gummed tape to reduce the thickness thereof at the junction of the same with the walls of the container;

IRVING MCHENRY. 

